Thoughts on voltage: 12.2V? Are you on a mooring?
10.9 V to the unit would most likely not turn it on, although you'd have to read the specs on the unit to find the range of voltages it requires.
Wiggling wires usually does nothing helpful, other than sometimes identifying a loose connection, or creating sparks!
I'd do two things: charge your house bank up to full for 12.7V (although you'd see the same voltage drop proportionally - but you may just may get the monitor to light), and replace the small power red + wiring, including those fuseholders that MS mentioned and carefully reconnect from the wires to those plugs into the shunt. Cut pretty far back from the plugs in case you have to do it over, you don't wanna run out of wire to those special plugs.
That's what I'd do if it was my boat.
Good luck.
Nice wiring job, BTW.